A series of tests were carried out to record the mechanical characteristics of the plaster ground of wallpaintings in the Mogao Grottoes. The tests were carried out on plaster ground test specimens. The parameters tested include grain density, sound velocity measurement, uniaxial compression, Brazilian tensile strength and direct shear strength. Based on the test results, mechanical characteristics such as density, Pwave velocity, Swave velocity, dynamic Poisson radio, compressive strength, elastic modulus, tensile strength, cohesive strength and internal friction angle were obtained. This information should be beneficial to the study of conservation and restoration of wallpaintings in the Mogao Grottoes.